Series-parallel electrical circuit

ABSTRACT

A direct current electrical circuit in which any number of electrical devices may be energized in parallel with each other to momentarily provide a higher state of energization of the devices, or in which the devices may be energized in series with each other to provide a lower state of energization of the devices, with the circuit automatically reverting from the parallel energization state to the series energization state. The invention is shown embodied in a trip coil circuit for a multi-pole electrical circuit breaker, such as a three-pole circuit breaker, in which each pole of the circuit breaker is provided with its own separate trip coil, including capacitor means in circuit with each respective trip coil whereby to place each respective trip coil electrically in parallel with the other trip coils across the direct current potential when the trip circuit is initially energized for tripping operation, and additional circuit means connecting the trip coils in series with each other across the direct current potential to provide an alternative current flow path for the trip coils when the capacitor means become substantially fully charged, and also to provide a series path through the trip coils whereby a supervisory signal device may monitor for trip circuit continuity prior to initiation of a tripping operation. The circuit thereby combines the advantages of the fast response time characteristic of a parallel circuit with the supervisory capability of a series circuit for monitoring circuit continuity of the plurality of trip coils.

[ 51 Dec. 26, 1972 [54] SERIES-PARALLEL ELECTRICAL CIRCUIT [72]Inventor: Zygmunt A. Wachta, Boston, Mass.

[73] Assignee: Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

22 Filed: May 26,1971

21 Appl.No.: 147,132

Primary Examiner-Robert K. Schaefer Assistant Examiner-William J. SmithAttorneyRobert C. Sullivan, Lee H. Kaiser and Robert B. Benson 57ABSTRACT A direct current electrical circuit in which any number ofelectrical devices may be energized in parallel with each other tomomentarily provide a higher state of energization of the devices, orin-which the devices may be energized in series with each other toprovide a lower state of energization of the devices, with the circuitautomatically reverting from the parallel energization state to theseries energization state.

The invention is shown embodied in a trip coil circuit for a multi-poleelectrical circuit breaker, such as a three-pole circuit breaker, inwhich each pole of the circuit breaker is provided with its own separatetrip coil, including capacitor means in circuit with each respectivetrip coil whereby to place each respective trip coil electrically inparallel with the other trip coils across the direct current potentialwhen the trip circuit is initially energized for tripping operation, andadditional circuit means connecting the trip coils in series with eachother across the direct current potential to provide an alternativecurrent flow path for the trip coils when the capacitor means becomesubstantially fully charged, and also to provide a series path throughthe trip coils whereby a supervisory signal device may monitor for tripcircuit continuity prior to initiation of a tripping operation. Thecircuit thereby combines the advantages of the fast response timecharacteristic of a parallel circuit with the supervisory capability ofa series circuit for monitoring circuit continuity of the plurality oftrip coils.

21 Claims, 1 Drawing Figure SERIES-PARALLEL ELECTRICAL CIRCUITBACKGROUND OF THE INVENTION Field of the Invention This inventionrelates to a direct current electrical circuit in which any number ofelectrical devices may be energized in parallel with each other tomomentarily provide a higher state of energization of the devices, or

in which the electrical devices may be energized in series with eachother to provide a lower state of energization of the devices, with thecircuit automatically reverting from the parallel energization state tothe series energization state.

In its broader sense the invention is applicable to circuits for theenergization of electrical devices such as solenoids, relays, counters,etc., in which it is desired to energize any number of devices inparallel to momentarily provide a higher energization stateof thedevices, with the circuit automatically reverting to a series connectionof the devices which provides a lower state of energization of thedevices.

The invention is particularly applicable to the energization of the tripcoil circuit of a multi-pole electrical circuit breaker, and will bedescribed in this environment. However, it will be understood that theinvention is not limited to the described embodiment.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS The subject matter of thepresent application is related to the subject matter of an applicationof Herbert M. Pflanz entitled Series-Parallel Electrical Circuit" filedconcurrently with the present application.

DESCRIPTION OF THE PRIOR ART ln'the prior art relating to trip coilcircuitry for multipole circuit breakers, such as three-pole circuitbreakers, in which each pole of the circuit breaker is provided with itsown separate trip coil, it has been known in the past to connect theplurality of trip coils either in a parallel circuit arrangement withrespect to each other, or, alternatively, in a series circuitarrangement with respect to each other. The parallel connection of theplurality of trip coils has the advantage of fast response time. Adisadvantage of the parallel connection of the trip coil circuits usedin the prior art, is the fact that it is not possible to have a singlered indicating light or other suitable indicating means supervise thetotal trip circuit prior to initiation of the tripping operation wherebyto indicate whether any one of the trip coils is open-circuited,'since,with the parallel arrangement of the trip coils, if the circuit of onetrip coil is open, the supervisory signal would still be connected topower through the other two parallel connected trip coils.

It is also known in the prior art instead of using the parallelconnection of the trip coil circuits as'hereinbefore described, toconnect the-trip coils in series with each other. The series connectionof the trip coils has the advantage that the supervisory signaling meanssuch as a red indicating light may be connected in series with theseries-connected trip coils to supervise or monitor the circuitcontinuity of all of the trip coils since if any one of theseries-connected trip coils has an open circuit, the red lightor othersupervisory signal will be extinguished. However, the series connectionof the trip-coils as just described, has the disadvantage that since thetrip circuit coil inductance is tripled, being the sum of theinductances of the three individual trip coils, the tripping currentthrough each trip-coil builds up slowly, thereby causing the seriesconnected trip-circuit to have a slow response time.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide an electrical circuit in which any number ofelectrical devices may be energized in parallel with each other tomomentarily provide a higher state of energization of the devices, or inwhich the electrical devices may be energized in series with each otherto provide a lower state of energization of the devices, and in whichthe circuit automatically reverts from the parallel energization stateto the series energization state.

It is another object of the present invention to provide trip circuitryfor a multi-pole circuit breaker in accordance with which the pluralityof trip coils are arranged to be energized for tripping operation inparallel with each other and to be deenergized in series with eachother. I

It is a further object of the invention to provide circuitry for thetrip coils of a multi-pole circuit breaker which combines the advantagesof both parallel-con nected trip coils of the prior art and ofseries-connected trip coils of the prior art.

It is a further object of the invention to provide trip coil circuitryfor a multi-pole circuit breaker which has the advantage of fasttripping response time characteristic of parallel-connected trip coils,while permitting a signal light or other supervisory means to monitorthe circuit continuity of the plurality of trip coils and theirreadiness to trip their respective breaker poles prior to actualinitiation of the tripping operation.

In achievement of these objectives, there is provided in accordance withthis invention a direct current electrical circuit in which any numberof electrical devices may be energized in parallel with each other tomomentarily provide a higher state of energization of the devices, or inwhich the electrical devices may be energized in series with each otherto provide a lower state of energization of the devices, with thecircuit automatically reverting from the parallel energization state tothe series energization state.

In a specific embodiment of the invention, there is provided a trip coilcircuit for a multi-pole electrical circuit breaker, such as athree-pole circuit breaker, in which each pole of the circuit breaker isprovided with its own separate trip coil, including capacitor means incircuit with each respective trip coil, whereby to place each respectivetrip coil in parallel with the other trip coils across the directcurrent potential when the trip vantages of the fast response timecharacteristic of a parallel circuit with the supervisory capability ofa series circuit for monitoring circuit continuity of the plurality oftrip coils. I

Further objects and advantages of the invention will become apparentfrom the following description taken in conjunction with theaccompanying drawing in which: I

BRIEF DESCRIPTION OF THE DRAWING The sole FIGURE is a circuit diagram ofimproved trip-circuitry for a multi-pole circuit breaker such asthree-pole circuit breaker, in accordance with an embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the circuitdiagram of the drawing, which is for a three-pole electrical circuitbreaker having poles Pl, P2 and P-3 in electrical lines L-l, L2 and L-3,respectively, the trip coils for the respective poles of the three-polecircuit breaker are indicated at A, 10B and 10C, respectively. Tripcoils 10A, 10B and 10C when energized respectively cause tripping toopen position of the respective breaker poles P-1, P-2 and P-3 as iswell known in the art. The tripping circuit of the drawing is connectedacross lines 18 and of a direct current power supply, such as 125 voltsD.C.

Connected in series with the trip-coils 10A, 10B and 10C is the normallyopen breaker-operated auxiliary contact 16, which is closed when thebreaker poles P-l, P-2, P-3 are closed. Contact 16 is operated to openposition in the opening operation of the breaker.

When the breaker is closed, and before any actuation of the trip circuithas occurred, the supervisory signal device 22, which may be a redlight, for example, is energized to indicate that the breaker is ready"to tripthat is, that there is circuit continuity through each of thetrip coils so that they will trip properly when the proper current pulseis supplied thereto, as will be hereinafter described. The supervisorysignal device 22 is energized through the following series circuit:

From the DC. power supply positive line 18 through auxiliary contact 16which is closed when the breaker is closed through current limitingresistor 24, through supervisory signal device (red light) 22, tojunction 40, through trip coil 10C, to junction 43, through resistance46, through blocking diode 47 which is conductive in the direction ofpositive to negative, to junction 34, through trip coil 10B, to junction38, through resistance 48 and inductance 50 to, junction 52,

1 through trip coil 10A, and thence to negative line 20 of the directcurrent power supply.

Thus, it will be seen that in the circuit of the drawing when thebreaker is closed and prior to initiation of a tripping operation, thesupervisory signal device 22 is connected in series with all three tripcoils 10A, 10B,

. 10C so that if any one of the trip coils has an open circuit and thusis inoperative, the red light or other supervisory signal 22 will beextinguished, giving a warning of the defective condition of the tripcircuit. It will be obvious, of course, that the deenergization of thesupervisory signal device 22 due to an open circuit in one of the tripcoils could instead be utilized through suitable relay means (not shown)to cause the energization of an alarm circuit.

In the series circuit just described in which the supervisorysignaldevice 22 is energized when the breaker is closed and prior toinitiation of a tripping operation, due to the use of current limitingresistor 24 in series with supervisory signal device 22, and also due tothe additional series resistance provided by resistors 46 and 48, thecurrent through trip coils 10A, 10B and v10C is not enough to energizethe trip coils sufficiently to cause them to trip their respectivebreaker poles to open position. Also, the values of the circuitconstants, such as the resistance values of signal device 22 and ofcurrent limiting resistor 24 are such that any charging of the variouscapacitors in the circuit prior to the initiation of the trippingoperation by closure of contact 26 is negligible and insignificant. Thetripping circuit is energized to perform the tripping operation byclosure of a normally open contact 26 which may be closed eithermanually or by a protective relay. During an actual tripping operation,closure of contact 26 shuntssupervisory signal 22 and resistor 24, sothat the red light 22 is extinguished during the actual trippingoperation.

While the circuit of the supervisory signal device 22 has been shown anddescribed as being energized only when the breaker is closed, withauxiliary contact 16 being closed, it is obvious that the circuit ofsupervisory signal 22 including current limiting resistor 24 could beconnected directly to positive line 18 without going throughbreaker-operated auxiliary contact 16 so that the supervisory signalcircuit would be energized across the direct currentpower source,regardless of whether the breaker was open or closed. In this case, thesupervisory signal 22 would monitor for trip coil circuit continuitywhen the breaker is open as well as when it is closed.

The parallel-series trip circuit can best be described in connectionwith its operation as follows:

When the contact 26 is closed to initiate tripping of the breaker, thethree trip-coils 10A, 10B and 10C are respectively initially energizedby a current pulse (the charging pulse to the capacitors in circuit withrespective trip coils) in a respective one of three parallel paths, asfollows:

1. Trip coil 10A is initially energized by a current pulse in thefollowing circuit path: From the line 18 of the direct current powersupply through auxiliary contact 16, through contact 26 to junctions 28and 40, through the parallel connected capacitors 30 and 32 to junction34, thence through capacitor 36 to one side of trip coil 10A, throughtrip coil 10A, and thence to conductor 20 of the direct current powersupply.

2. Trip coil 10B is initially energized by a current pulse in thefollowing circuit path: From line 18 of the DC. power supply, throughauxiliary contact 16, through closed contact 26 to junctions 28 and 40,through the parallel connected capacitors 30 and 32 to the junction 34,thence through trip coil 108, to junction 38 and through the parallelconnected capacitors 41 and 42 to line 20 of the DC. power supply.

3. Trip coil 10C is initially energized by a current pulse in thefollowing circuit path:

From line 18 of the DC. power supply through auxiliary contact 16,through closed contact 26, through junctions 28 and 40 to one side oftrip coil C, through trip coil 10C, to junction 43, thence throughcapacitor 44 to junction 38, and thence through parallel connectedcapacitors 41 and 42 to the negative line of the power supply,

At the moment of initial closure of contact 26, a momentary chargingcurrent to the respective capacitors in each of the parallel trip coilcircuits just described passes through the respective trip coils 10A,10B and 10C. This momentary charging current to the capacitors in eachof the respective parallel circuits energizes the respective trip coils10A, 10B and 10C sufficiently to trip each of the respective breakerpoles P-l, P-2 and-P-3 corresponding to the respective trip coils 10A,10B and 10C, thereby providing a fast response time for tripping of therespective breaker poles.

After the initial rush of charging current which provides the pulse tothe respective trip-coils 10A, 10B and 10C sufficient to trip thebreaker poles, as just explained, the various capacitors in thecircuitry just described, namely, capacitors 30, 32, 36, 41, 42 and 44become substantially completely charged and therefore nonconducting tofurther flow of direct current in the parallel paths just enumerated.When the capacitors in the circuitry become nonconducting to furtherflow of direct current, the current then must flow through the 3 threetrip coils 10A, 10B and 10C in only the following series path:

From the D.C. power supply positive line 18 through contact 16, throughcontact 26, past junctions 28 and 40, through trip coil 10C, to junction43, through resistance 46, through blocking diode 47 which is conductivein the direction of positive to negative, to junction 34, through tripcoil 108, to junction 38, through resistance 48 and inductance 50 tojunction 52, through trip coil 10A, and thence to negative line 20 ofthe direct current power supply.

The use of the blocking diode 47 in series with resistor 46 and of theinductance 50 in series with the resistor 48 are refinements which arenot fundamental to the operation of the circuit but are merely for thepurpose of reducing or minimizing wasted current flow through theresistors 46 and 48 during the initial energization period after closureof contact 26 when the resistors 46 and 48'are electrically in parallelwith the trip coils.

During the later phase of the breaker opening operation, when thecurrent flow to the trip coils 10A, 10B and 10C follows the series pathin which the trip coils are connected in series, the current flowthrough the series-connected trip coils is reduced due to the fact thatthe resistances of the three trip coils 10A, 10B and 10C are connectedin series with each other and in series with resistors 46 and 48. Thisresults in a reduced flowof current in the series circuit of the tripcoils 10A, 10B and 10C, resulting in smaller shut-off current when thebreaker operated auxiliary contact 16 is opened during the final phaseof the opening movement of the breaker. This reduced current in theseries circuit just described minimizes arcing at the auxiliary contact16.

All of the capacitors shown in the circuitry are assumed to have thesame value of capacitance. That is, each capacitor has a value of Cmicrofarads.

The capacitance of the capacitors in the circuits of the trip coils areso related to the time required for the auxiliary contact 16 to openthat the capacitors have become substantially fully charged andnonconductive to further direct current flow before the auxiliarycontact 16 has completely opened. Therefore, during the later phase ofthe opening movement of the breaker and of the auxiliary contact thetrip coils are connected in series with each other, resulting in asmaller shut-off current in the trip circuit during the final phase ofthe breaker opening operation, which minimizes arcing at the auxiliarycontact, as previously mentioned.

After the circuit breaker has opened, with the resultingopening of thebreaker operated auxiliary contact 16, the entire tripping circuit isthen disconnected from the positive bus 18 so that the chargedcapacitors in the circuit such as capacitors 30, 32, 36, 41, 42 and 44may then discharge in preparation for a subsequent tripping operation.For example, the capacitor 44 would discharge in alocalized circuit fromthe right hand side of capacitor 44 as shown in the drawing, to junction43, through resistance 46, through blocking diode 47 to junction 34,through trip coil 103, to junction 38, and thence back to the oppositeside or left-hand side with respect to the view shown in the drawingofthe capacitor 44. The other capacitors of the circuitry would dischargea similar manner through corresponding 10- calized circuits.

it is apparent that in its broader sense the invention is applicable tocircuits for energizing any number of electrical devices such assolenoids, relays, counters, etc.', in which it is desired to energize amultiplicity of such devices in parallel to momentarily provide a higherstate of energization of the devices, with the circuit automaticallyreverting to a series connection of the devices which provides a lowerstate of energization of the devices.

It can also be seen from the foregoing that there is provided inaccordance with a specific embodiment of the present invention a circuitarrangement for the energization of the trip coils of a multipolecircuit breaker in accordance with which the trip coils are effectivelyconnected in parallel with each other during the initial phase of thebreaker opening operation, thereby providing a fast response time of thetrip coils which provides fast tripping of the circuit breaker, and withthe plurality of trip coils being effectively connected in series witheach other during the later phase of the breaker opening operation,whereby to provide a lower current through the series connected tripcoils when they are being deenergized, which minimizes arcing at theauxiliarycontact 16 during the opening of the breaker-operated auxiliarycontact. Furthermore, the series connection of the trip coils in thecircuitry arrangement permits the red light or other supervisory signalto be connected in series with the plurality of trip coils whereby toprovide an indication prior to initiation of the tripping operation ofwhether or not there is a continuous circuit through the trip coils, asan indication of a possible open circuit condition in any one of thetrip coils.

While in the specific embodiment described hereinbefore, the controlcircuit has been shown controlling the tripping operation of each poleof a single multipole breaker, it is obvious that a circuit of the typeshown may be used to control theopening of each pole of two or moremulti-pole breakers when simultaneous opening of a plurality ofmulti-pole breakers is desired.

From the foregoing detailed description of the present invention, it hasbeen shown how the objects of the invention have been obtained in apreferred manner. However, modifications and equivalents of thedisclosed concepts such as readily occur to those skilled in the art areintended to be included within the scope of this invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A direct current electrical energization circuit for a plurality ofelectrical devices, comprising a corresponding first circuit path foreach of said devices including capacitor means in series with eachrespective device, each of said first circuit paths being connectedacross a direct current supply when said circuit is energi zed wherebyto place said plurality of devices in parallel current flow relation toeach other in series with their corresponding capacitor means whereby tosupply a current pulse to each respective device when said capacitormeans are charging upon initial energization of said circuit, saidcapacitor means becoming substantially nonconductive to further flow ofdirect current in the respective firs circuit paths upon becomingsubstantially fully charged, said circuit comprising additional circuitmeans connecting said devices in series with each other across thesource of direct current potential in a circuit path excluding saidcapacitor means whereby to provide an alternative current flow path forsaid devices when said capacitor means become substantially fullycharged.

2. A direct current electrical energization circuit as defined in claim1 in which said additional circuit means comprises at least oneresistor.

3. A direct current electrical energization circuit as defined in claim1 in which said plurality of electrical devices are the trip coils for amulti-pole electrical circuit breaker.

4. In combination, a multi-pole electrical circuit breaker having aseparate trip coil operatively associated with each pole for trippingthe respective pole to an open position upon energization of thecorresponding trip coil, an energization circuit for said trip coils,said energization circuit comprising contact means adapted to connectsaid circuit to a direct current potential to initiate trippingoperation of the breaker, said separate trip coil corresponding to eachpole of the breaker being connected in said energization circuit, acorresponding first circuit path for each trip coil including capacitormeans in circuit with the respective trip coil, each of said firstcircuit paths being connected across the direct current potential whensaid contact means is closed whereby to place each trip coil in parallelcurrent flow relation with the other trip coils when said capacitormeans are charging upon initial closure of said contact means, saidcapacitor means becoming substantially nonconductive to further flow ofdirect current in the respective first circuit paths upon becomingsubstantially fully charged, said energization circuit comprisingadditional circuit means connecting said trip coils in series with eachother and in series with said contact means across the source of directcurrent potential in a circuit path excluding said capacitor meanswhereby to provide an alternative current flow path for said trip coilswhen said capacitor means become substantially fully charged.

5. The combination defined in claim 4 comprising a supervisory signalmeans connected in circuit with all of the series-connected trip coilsindependently of said contact means whereby to monitor the circuitcontinuity of all of said trip coils.

6. The combination defined in claim 4 in which said additional circuitmeans comprises at least one resistor.

7. The combination defined in claim 4 in which said multi-poleelectrical circuit breaker has three poles.

8. The combination defined in claim 4 in which said first circuit pathfor each trip coil includes capacitor means in series with therespective trip coil.

9. A trip coil circuit for a multi-pole electrical circuit breaker ofthe type having a separate trip coil operatively associated with eachpole for tripping the respective pole to an open position uponenergization of the corresponding trip coil, said circuit comprisingcontact means adapted to connect said circuit to a direct cu rrentpotential to initiate tripping operation of the breaker, said separatetrip coil corresponding to each pole of the breaker being connected insaid circuit, a corresponding first circuit path for each trip coilincluding capacitor means in circuit with the respective trip coil. eachof said first circuit paths being connectedacross the direct currentpotential when said contact means is closed whereby to place each tripcoil in parallel current flow relation with the other trip coils whensaid capacitor means are charging upon closure of said contact means,said capacitor means becoming substantially nonconductive to furtherflow of direct current in the respective first circuit paths uponbecoming substantially fully charged, said circuit comprising additionalcircuit means connecting said trip coils in series with each other andin series with said contact means across the source of direct currentpotential in a circuit path excluding said capacitor means whereby toprovide an alternative current flow path for said trip C0118 when saidcapacitor means become substantially fully charged.

10. A trip coil circuit as defined inclaim 9 comprising a supervisorysignal means connected in circuit with all of the series-connected tripcoils independently of said contact means whereby to monitor the circuitcontinuity of all of said trip coils.

11. A trip coil circuit as defined in claim 9 in which said additionalcircuit means comprises at least one resistor.

12. A trip coil circuit as defined in claim 9 in which said multi-poleelectrical circuit breaker has three poles.

13. A trip coil circuit as defined in claim 9 in which said firstcircuit path for each trip coil includes capacitor means in series withthe respective trip coil.

14. In combination, a multi-pole electrical circuit breaker having aseparate trip coil operatively associated with each polefor tripping therespective pole to an open position upon energization of thecorresponding trip coil, an energization circuit for said trip coils,said separate trip coil corresponding to each pole of the breaker beingconnected in said energization circuit, said energization circuitincluding a corresponding first circuit path for each trip coilincluding capacitor means in circuit with the respective trip coil, eachof said first circuit paths being adapted tobe connected across thedirect current potential in response to initiation of a breaker trippingoperation whereby to place each trip coil in parallel current flowrelation with the other trip coils during the interval when saidcapacitor means are charging upon initial connection of the respectivesaid first circuit path to said direct current potential, said capacitormeans becoming substantially nonconductive to further flow of directcurrent in the respective first circuit paths upon becomingsubstantially fully charged, said energization circuit comprisingadditional circuit means connecting said trip coils in series with eachother in a circuit path excluding said capacitor means and adapted to beconnected across the source of direct current potential whereby toprovide an alternative current flow path for said trip coils when saidcapacitor means become substantially fully charged, and a supervisorysignal means connected in series with all of the series-connected tripcoils in said alternative current flow path and adapted to be connectedacross the direct current potential whenever the breaker is in closedposition whereby to continuously monitor the circuit continuity of allof said trip coils.

15. The combination defined in claim 14 in which said first circuit pathfor each trip coil includes capacitor means in series with therespective trip coil.

16. The combination defined in claim 14 in which said additional circuitmeans comprises at least one resistor.

17. The combination defined in claim 14 in which said multi-poleelectrical circuit breaker has three poles.

18. A trip coil circuit for a multi-pole electrical circuit breaker ofthe type having a separate trip coil operatively associated with eachpole for tripping the respective pole to an open position uponenergization of the corresponding trip coil, a separate trip coilcorresponding to each pole of the breaker being connected in saidcircuit, said circuit including a corresponding first circuit path foreachtrip coil including capacitor means in circuit with the respectivetrip coil, each of said first circuit paths being adapted to beconnected across a direct current potential in response to initiation ofa breaker'tripping operation whereby to place each trip coil in parallelcurrent flow relation with the other trip coils during the interval whensaid capacitor means are charging upon initial connection of therespective said first circuit paths to said direct current potential,said capacitor means becoming substantially nonconductive to furtherflow of direct current in the respective first circuit paths uponbecoming substantially fully charged, said circuit comprising additionalcircuit means connecting said trip coils in series with each other in acircuit path excluding said capacitor means and adapted to beconnectedacross the source of direct current potential whereby to provide analternative current flow path for said trip coils when said capacitormeans become substantially fully charged, and a supervisory signal meansconnected in series with all of the series-connected trip coils in saidalternative current flow path and adapted to be connected across thedirect current potential whenever the breaker is in closed positionwhereby to continuousl monitor the circuit continuity of all of saidtrip C01 5 when said breaker is in closed position.

19. A trip coil circuit as defined in claim 18 in which said firstcircuit path for each trip coil includes capaci' tor means in serieswith the respective trip coil.

20. A trip coil circuit as defined in claim 18 in which said additionalcircuit means comprises at least one resistor.

21. A trip coil circuit as defined in claim 18 in which said multi-poleelectrical circuit breaker has three poles.

I 060 l 2 C090

1. A direct current electrical energization circuit for a plurality ofelectrical devices, comprising a corresponding first circuit path foreach of said devices including capacitor means in series with eachrespective device, each of said first circuit paths being connectedacross a direct current supply when said circuit is energized whereby toplace said plurality of devices in parallel current flow relation toeach other in series with their corresponding capacitor means whereby tosupply a current pulse to each respective device when said capacitormeans are charging upon initial energization of said circuit, saidcapacitor means becoming substantially nonconductive to further flow ofdirect current in the respective firs circuit paths upon becomingsubstantially fully charged, said circuit comprising additional circuitmeans connecting said devices in series with each other across thesource of direct current potential in a circuit path excluding saidcapacitor means whereby to provide an alternative current flow path forsaid devices when said capacitor means become substantially fullycharged.
 2. A direct current electrical energization circuit as definedin claim 1 in which said additional circuit mEans comprises at least oneresistor.
 3. A direct current electrical energization circuit as definedin claim 1 in which said plurality of electrical devices are the tripcoils for a multi-pole electrical circuit breaker.
 4. In combination, amulti-pole electrical circuit breaker having a separate trip coiloperatively associated with each pole for tripping the respective poleto an open position upon energization of the corresponding trip coil, anenergization circuit for said trip coils, said energization circuitcomprising contact means adapted to connect said circuit to a directcurrent potential to initiate tripping operation of the breaker, saidseparate trip coil corresponding to each pole of the breaker beingconnected in said energization circuit, a corresponding first circuitpath for each trip coil including capacitor means in circuit with therespective trip coil, each of said first circuit paths being connectedacross the direct current potential when said contact means is closedwhereby to place each trip coil in parallel current flow relation withthe other trip coils when said capacitor means are charging upon initialclosure of said contact means, said capacitor means becomingsubstantially nonconductive to further flow of direct current in therespective first circuit paths upon becoming substantially fullycharged, said energization circuit comprising additional circuit meansconnecting said trip coils in series with each other and in series withsaid contact means across the source of direct current potential in acircuit path excluding said capacitor means whereby to provide analternative current flow path for said trip coils when said capacitormeans become substantially fully charged.
 5. The combination defined inclaim 4 comprising a supervisory signal means connected in circuit withall of the series-connected trip coils independently of said contactmeans whereby to monitor the circuit continuity of all of said tripcoils.
 6. The combination defined in claim 4 in which said additionalcircuit means comprises at least one resistor.
 7. The combinationdefined in claim 4 in which said multi-pole electrical circuit breakerhas three poles.
 8. The combination defined in claim 4 in which saidfirst circuit path for each trip coil includes capacitor means in serieswith the respective trip coil.
 9. A trip coil circuit for a multi-poleelectrical circuit breaker of the type having a separate trip coiloperatively associated with each pole for tripping the respective poleto an open position upon energization of the corresponding trip coil,said circuit comprising contact means adapted to connect said circuit toa direct current potential to initiate tripping operation of thebreaker, said separate trip coil corresponding to each pole of thebreaker being connected in said circuit, a corresponding first circuitpath for each trip coil including capacitor means in circuit with therespective trip coil, each of said first circuit paths being connectedacross the direct current potential when said contact means is closedwhereby to place each trip coil in parallel current flow relation withthe other trip coils when said capacitor means are charging upon closureof said contact means, said capacitor means becoming substantiallynonconductive to further flow of direct current in the respective firstcircuit paths upon becoming substantially fully charged, said circuitcomprising additional circuit means connecting said trip coils in serieswith each other and in series with said contact means across the sourceof direct current potential in a circuit path excluding said capacitormeans whereby to provide an alternative current flow path for said tripcoils when said capacitor means become substantially fully charged. 10.A trip coil circuit as defined in claim 9 comprising a supervisorysignal means connected in circuit with all of the series-connected tripcoils independently of said contact means whereby to monitor the circuitcOntinuity of all of said trip coils.
 11. A trip coil circuit as definedin claim 9 in which said additional circuit means comprises at least oneresistor.
 12. A trip coil circuit as defined in claim 9 in which saidmulti-pole electrical circuit breaker has three poles.
 13. A trip coilcircuit as defined in claim 9 in which said first circuit path for eachtrip coil includes capacitor means in series with the respective tripcoil.
 14. In combination, a multi-pole electrical circuit breaker havinga separate trip coil operatively associated with each pole for trippingthe respective pole to an open position upon energization of thecorresponding trip coil, an energization circuit for said trip coils,said separate trip coil corresponding to each pole of the breaker beingconnected in said energization circuit, said energization circuitincluding a corresponding first circuit path for each trip coilincluding capacitor means in circuit with the respective trip coil, eachof said first circuit paths being adapted to be connected across thedirect current potential in response to initiation of a breaker trippingoperation whereby to place each trip coil in parallel current flowrelation with the other trip coils during the interval when saidcapacitor means are charging upon initial connection of the respectivesaid first circuit path to said direct current potential, said capacitormeans becoming substantially nonconductive to further flow of directcurrent in the respective first circuit paths upon becomingsubstantially fully charged, said energization circuit comprisingadditional circuit means connecting said trip coils in series with eachother in a circuit path excluding said capacitor means and adapted to beconnected across the source of direct current potential whereby toprovide an alternative current flow path for said trip coils when saidcapacitor means become substantially fully charged, and a supervisorysignal means connected in series with all of the series-connected tripcoils in said alternative current flow path and adapted to be connectedacross the direct current potential whenever the breaker is in closedposition whereby to continuously monitor the circuit continuity of allof said trip coils.
 15. The combination defined in claim 14 in whichsaid first circuit path for each trip coil includes capacitor means inseries with the respective trip coil.
 16. The combination defined inclaim 14 in which said additional circuit means comprises at least oneresistor.
 17. The combination defined in claim 14 in which saidmulti-pole electrical circuit breaker has three poles.
 18. A trip coilcircuit for a multi-pole electrical circuit breaker of the type having aseparate trip coil operatively associated with each pole for trippingthe respective pole to an open position upon energization of thecorresponding trip coil, a separate trip coil corresponding to each poleof the breaker being connected in said circuit, said circuit including acorresponding first circuit path for each trip coil including capacitormeans in circuit with the respective trip coil, each of said firstcircuit paths being adapted to be connected across a direct currentpotential in response to initiation of a breaker tripping operationwhereby to place each trip coil in parallel current flow relation withthe other trip coils during the interval when said capacitor means arecharging upon initial connection of the respective said first circuitpaths to said direct current potential, said capacitor means becomingsubstantially nonconductive to further flow of direct current in therespective first circuit paths upon becoming substantially fullycharged, said circuit comprising additional circuit means connectingsaid trip coils in series with each other in a circuit path excludingsaid capacitor means and adapted to be connected across the source ofdirect current potential whereby to provide an alternative current flowpath for said trip coils when said capacitor means Become substantiallyfully charged, and a supervisory signal means connected in series withall of the series-connected trip coils in said alternative current flowpath and adapted to be connected across the direct current potentialwhenever the breaker is in closed position whereby to continuouslymonitor the circuit continuity of all of said trip coils when saidbreaker is in closed position.
 19. A trip coil circuit as defined inclaim 18 in which said first circuit path for each trip coil includescapacitor means in series with the respective trip coil.
 20. A trip coilcircuit as defined in claim 18 in which said additional circuit meanscomprises at least one resistor.
 21. A trip coil circuit as defined inclaim 18 in which said multi-pole electrical circuit breaker has threepoles.